The present disclosure relates generally to inkjet ink sets.
An inkjet printing system generally includes a printhead and an ink source which supplies liquid ink to the printhead. The printhead ejects ink drops through a plurality of orifices or nozzles and onto a print media, such as paper. Typically, the nozzles are arranged in one or more arrays such that properly sequenced ejection of ink from the nozzles causes characters or other images to be printed upon the print media as the printhead and the print media are moved relative to each other.
Inkjet ink sets used in inkjet printing systems often include four, six or eight different colored inks. Generally, the colors included in such ink sets are one or more shades of cyan, magenta, yellow and/or black. The inks of the set are combined together to form secondary colors. The combination of two or more colored inkjet inks may result in a printed image having substantially non-uniform gloss, due, at least in part, to the roughness of the mixed ink film. The combination of two or more inks may also have a relatively high ink flux. Blotchiness of the filled area (i.e., coalescence) may result at high density areas when the ink flux exceeds the capacity of the media. When the printed image does exhibit such undesirable characteristics, the characteristics often manifest themselves at relatively high ink density areas.
The addition of more colors (e.g., green, red, blue, etc.) to an ink set may be problematic, as these extended colors tend to have multivalent ion contaminants. After repeated use, these contaminants may be deposited onto printhead resistors as a film build-up. This build-up may reduce the thermal efficiency of heat transfer, which reduces the ink drop velocity and drop weight, resulting in less color saturation and banding.